Remote-control system



July 26, 1949.

Original Filed Aug.

H. G. EVERS REMOTE-CONTROL SYSTEM 3 Sheets-Sheet 1 INVENTOR. H'AR RY G. EVERS ATTORNEY H. G. EVERS I REMOTE-CONTROL SYSTEM July 26, 1949.

3 Sheets-Sheet 2 Original Filed Aug. 21, 1944 mOmN Wmo N mm m HARRY G. EVERS ZZZ 4:14

ATTO RN EY July 26, 1949. H. G. EVERS REMOTE1CQNTROL SYSTEM 3 Sheets-Sheet 3 Original Filed Aug. 21, 1944 IN VEN TOR. HARRY G E VE R S 2% 44 ATTORNEY Patented July 26, 1949 UNETED STATES FATENT OFFICE REMGTE- JONTRGL SYSTEM Harry G. Evers, Newark, N. 3., assignor to Automatic Electric Laboratories, Inc Chicago, ,Ill. a corporation of Delaware 9 Claims. 1.

The present invention relates in general to code transmitters and particularly to a code transmitter for a remote control system which employs a plurality of signaling channels to control a multiplicity of functions at a number of remote stations either simultaneously or selectively.

The present case is a division of my ,copending application, Serial No. 550,362; filed August 21, 1944; entitled Remote control systems.

The disclosure'illustrating one embodiment of the invention is used to control the operation of hree aircraft, selectively or simultaneously, from a fourth control aircraft by means of a radio frequency carrier upon which ten audio frequency signaling tones'may be superimposed. It is to be understood that the invention is not limited to the control of aircraft as it-will be apparent that it is readily adapted to the control of other'moving vehicles or stationary equipment either by means of the radio link illustrated or by wire lines,

The principal object of the'present invention is to provide a codesender that is capable of transmitting a multiplicity of codes at a rapid rate through the efficient use of a, plurality of signaling channels, but without requiring the use of more thanone channel at a time.

A further object of the invention is to provide a code sender having code selecting means that is common toa plurality of groups of control keys each of which controls a separate function.

Another object is to provide means for allowing preferential use of thexcode selecting means by certain of the groups of control keys.

Still another object is to provide a novel arrangement for transmitting codes in sequence when the key operations overlap.

A still further object is to provide a novel method of initiating the operation of the code sender in response to the operation of a control key.

Other objects of the invention will appear upon a further perusal of the specification and the accompanying drawings, in which:

Figs. 1, 2 and 3, when placed side by side in the order named, comprise a schematic diagram of the switching equipment employed in the control plane.

As previously mentioned, ten audio frequency tones, any one of which may be superimposed on a radio frequency carrier, are employed to control three airplanessimultaneously or selectively. Four of these tones are used for directing the controlled planes up, down, right, or left. Two

Ill

2' r more of the tones are used for increasing or decreasing any one of ten variable functions previously selected by the switching equipment as will presently be described. The remaining four tones are used for the controlof the switching equipment constituting the invention. Of the latter four tones, one is used to control a group of distributor relays in the controlled plane, and each of the other three tones .controls a group of register relays in conjunction with the distributor relays. Each control signal consists of a seizure pulse of one of thesetthree tonesfollowed by five pulses of the tone which controls the distributor relays. Duringv .none, .or anyone or two, of the four spaces between. the five pulses the same tone used for seizure may be repeated. The distributor relays prepare a circuit to a different one of four relays in the register corresponding to the seizure tone during eachof the four spaces between the five tone pulses. When the seizure tone is repeated during these spaces the corresponding relays in the register are operated. The various combinations which can be formed by operating none, or any one or two, of the four relay-s permits ten functions to be controlled by a register.

in the first register four of the ten possible functions are used for plane selection and two more are used for aileron control. The second register is used for controlling five apparatus units, each of which has two possible operated conditions. The ten possible combinations in the third register are used to prepare any two of twenty circuits associated with ten apparatus units. Either-one of the two selected circuits may then be completed for as long an interval as desired by 'theincrease or decrease tone to turn on or off, or to increase or decrease the degree of operation of, theselected one of the ten apparatus units.

The coded signals are produced in the control equipment by a relay type code sender and a group of ten code selecting "relays. A group. of control keys, or switches, is provided for each group of functions. Each key in a group corresponds to one of the code selectingrelays so that the code transmitted depends upon which key in a group is operated. The same codes are used by all groups but the particular one of the three tones used for seizure and function selection depends upon the-groupin which a key is operated. This latter tone selection is accomplished by two relay groups, each orwhich' is associated with one of the key groups. These latter relay groups also cause signals to be transmitted in the drawing. These keys are of the mechanicalinterlocking type in which the operation of any key releases a previously operated key and latches itself operated. A set of common springs CH are also provided and are arranged to be momentarily operated by the latching bar when any of the selecting keys is operated. The group of four keys Al to A4 at the left center portion of the drawing is used for plane selection. These keys are also of the mechanical interlocking type and common springs A5 are also provided for this group. At the lower left there is shown the increase-decrease key l8 and the quadrant switch 20. The quadrant switch consists of a shaft that is flexibly mounted near one end so as to normally occupy a vertical position, but permitting its free end to be displaced forward, backward, or laterally in the same fashion as the control stick in an airplane. Four snap-action switches are positioned about the shaft at 90 intervals so as to permit selective operation of any one of the switches by movement of the free end of the shaft. The forward and backward motion of the quadrant switch operates the elevators of the controlled planes, while the lateral motion of thequadrant switch controls the rudders, either alone or in conjunction with the ailerons depending upon whether a switch 23 located within the shaft of the quadrant switch is operated or released. Two ordinary relays, lllfl and H8, and two mechanically interlocked relays, I and :33, are controlled by switch 2! to accomplish this result in a manner to be described presently. Relays I to I68 are storage relays associated with the plane selection key group, and relays I73 to l 98 are similar storage relays associated with the variable function selectin key group.

In Fig. 2 five single pole double throw toggle switches Bl to B5 are shown at the top of the drawing. Each toggle switch is associated with a pair of mechanically interlocked relays like 2803 and 2MB. Each of these mechanical interlocking relays is in turn associated with one of the ten code selecting relays 200 to 299 shown at the center of the drawing. Relay 200T shown at the left transfers the code selecting relays from the mechanically interlocked relays to contacts of the storage relays I and I of Fig. 1 when one of the mechanically interlocking push keys of Fig. 1 is operated. The three remaining relays 210s to 2308 at the right of the drawing are start and lockout relays which start the code sender of Fig. 3 whenever one of the the code selecting relays is operated and also prevent any new codes from being registered until a previously registered code has been transmitted.

The relays shown in Fig. 3 constituting the code sender consist of a pair of pulse generating relays 300 and 310, a pulse directing relay 32c, and five counting relays 339 to 370, At the right of the drawing a radio transmitter and ten audio frequency oscillators are illustrated in block form. It should be noted that although ten separate oscillators have been illustrated for convenience, a single oscillator will sufi'ice if it is arranged so that its frequency is controlled by operated at the same time by mistake.

the switching equipment. This is possible because only a single frequency is required at a time and can readily be accomplished by using a conventional vacuum tube oscillator in which the frequency is determined by resistance and capacitance, or inductance and capacitance elements, by providing ten sets of frequency determining elements and connecting the proper set in the oscillating circuit by keying relays controlled over the leads which are shown terminating in oscillators OSC. l to 080. I0.

Returning now to Fig. 1, the transmission of a signal to effect a plane selection will be described in detail. As previously mentioned, plane selection is accomplished by the four key strip of interlocking push keys Al to A4. Assuming that it is desired to control plane I individually, key AI will be operated. The operation of key A! releases any previously operated key, momentarily operates the common springs A5, and prepares a circuit to code selecting relay 226 from battery at contacts of relay 230s over lead 39, through operated contacts Al to contacts of relay lfiil. The momentary operation of the common springs A5 completes a circuit to relay [Ml causing it to operate and lock itself by its own make contacts. Relay M0 completes a circuit to relay i555 from battery at contacts 2| is, through contacts 2213, over lead 3i through contacts Hi! and I81. This latter circuit will be completed only if the code selecting relays are free. If there is a code transmission in progress relays EMS and 220s will be operated and hence the circuit to relay (50 will not be completed until the previously registered code has been sent. When relay I50 operates it closes its looking circuit to contacts of relay I48, closes a circult to relay I60, prepares a circuit for shunting down relay M0 over lead 32, and closes a circuit to relay 269T over lead 33. Relay I fill operates, prepares its locking circuit to lead 34, and connects all of the plane selecting keys, Al to A i, to contacts of relay 200T. Relay 200T operates; prepares its locking circuit to contacts of relay ELliS; prepares a circuit to 080. 2 from contacts of the code selecting relays over lead 45, through contacts of relay 290T to lead 35, over lead 35 to contacts of relay I89, and thence over lead 36 to OCS. 2; and completes the connections from the plane selecting keys A! to A4, to code selecting relays are to 259, respectively. A circuit is thus completed to relay 220 from battery over lead at through contacts of key AI, contacts of relay E60, lead 31, contacts of relay 200T, through the winding of relay 229, through the chain contacts of the succeeding code selecting relays 23a to 290 to lead 38, and over lead 38 to battery, or ground, at contacts of relay 330.

The purpose of the chain contacts in the circuit last traced is to prevent more than one code selecting relay from being operated at the same time. In the present case this serves as a precaution to prevent a false code from being transmitted if two of the interlocking push keys were However, as will belater described, it is intended that several of the toggle switches, Bl to B5, may be operated at the same time and in that case the chain circuit causes the codes corresponding to each toggle switch operation to be sent in sequence. 7

Relay 22E! operates over the previously traced circuit, prepares its locking circuit through relay 25GB, closes a circuit to relay 2308, and connects lead 45 to lead 42 so as to operate 030. I

the code sender.

during the second spacing interval. Relay Zi-IBS operates, removes battery from lead 39 thus opening the operating circuit to relay 22d and removing a short circuit from relay 219s, and completes the locking circuit for relay 29M. Re lay EH25 operates in series With relay 229 from battery over lead 33, closes a circuit to relay 225$, closes a locking circuit to relay I60 over lead 33, removes battery from lead 3! to guard the code selecting relays, and short-circuits relay M8 over lead 32. Relay I46 restores and opens the locking circuit to relay 158. Relay lEiJ restores and opens the opera-ting circuits to relays ltd and 286T.

When relay ZltS operated it also completed a circuit to 053C. 2 from ground at contacts 3H through contacts 8'55, over lead 3Q, through contacts 252s and thence over the previously traced circuit including leads d3, 35, and as to the oscillator. The operation of 080. 2 modulates the radio frequency carrier roduced by the transmitter at a particular audio frequency. The carrier is demodulated by "the radio receiver in the controlled plane and th audio frequency signal causes a register therein to be seized.

The above operations complete the registration of the code'to be transmitted and the seizure of a register in the controlled plane. The code transmission is started by the operation of relay EZQS which extends battery over lead 15 to A circuit is closed to relay 31?; from battery on lead 3-5 causing it to operate and close a circuit to relay 3E9. Relay sec operates and opens the circuit to relay em. Relay tic r stores and opens the circuit to relay 3% which restores an'd recloses the circuit to relay did. This cycle of operations is repeated five times for each transmission of a signal as determined by counting relays 33a to 315. The speed and the Iper cent closure time of the contacts of relay till is governed bythe operate and release times or relays 33d and 3H Relay are is made slow-to-release by a copper sleeve on its core. Relay 3953 is made slow-to-release by an adjustable shunting resistor. preferably made slightly slow to operate by using a relatively largenumber of turns inits winding in order to secure the optimum per cent closure time of the contacts of relay 3H3. During the first operation of relay Sill, contacts 311 transfer ground from 0530. 2 to QSC. Land contacts 362 close a circuit to relay 31E. Relay 3 10 operates, closes its locking circuit :to lead '46, prepares circ'uits to relays 32d and sec atcontacts 372 and 333, and prepares a circuit for connecting ground to lead ll through contacts 31 during th'e first restoration ofr'elay Sid. "Thefirst'restoraticn of relay 3 i o grounds lead d1, closes a circuit torelay are through contacts slaand'opeh'sthe operating circuit to relay 37o. Relay 32'0 operates. closes its locking circuit through contacts 372,

and prepares a circuit to relay 389 through con- 'tacts 373. The second operation of relay SIG completes a circuit torelay 356 at contactsfil-t, transfers ground from :lead M to 050. "I, and

closes aiurtliercircuit to-relay $28. Relay 35?! operates, closes its locking circuit,prepares-a circuit to relay 3%, opens the operating circuit to relay 52c, prepares a circuit to ground ile'ad during the second restoration of relay 3H3. When relay Eli? restores the second'tim'eit opens the locking circuit to relay-32d, opens :thecperating circuit to relay 36$, andggroundslead '42 which causes the operation 'of'CJEiC. 2 .si n'celead 32' is connected to dead 55 :by rcodeselecting "relay Relay 30B is also 2%. Subsequent operations and restorations of relay no cause the successive operations of counting relays 35d, 34 i] and 33% in conjimction with the operation of relay 3%. OSC. I :is operated during each operation of relay 3-H! and leads to and M are grounded during the successive restorations Of relay 3H3. When relay 33d operates upon the fifth operation of relay 34% iii; removes battery from lead 36 to release relays 22d and 298$, opens the locking circuit to counting relays 3&5 to 3W3, closes its own locking cir= cult, and connects battery from operated contacts on relay 3m to lead 55 to hold relay 22-05 when relay 2. restores. Relays 3% to 31:0 restore. Relay 22c restores and opens the circuit to relay Relay ems restores, opens the operating circuit to relay 22%, and opens the locking circuit to relay oi Belay rec restores. Relay 3'59 restores, opens the circuitto relay .359; and opens the locking circuits to relays 2:265 and Relay sec restores. Relay sacs restores after its slow release period and connects :ba-ttery to lead 3! to enable anew registration to be made.

The operation of the code sender interrupted the operation of SS0. 2 and caused five successive operations of CS0. t. ed during the second spacing interval between the five pulses. If pIan'e seIecting keyAE operated'a similar cycle of operations occurs except that code selecting relay 2% will be operatedzinstead of relay are causing 080. '2 tube operated during the third spacing interval instead of the second. Similarly, when plane selecting :key is operated, code selecting relay 2% will :bfenperated instead of relay 2% causing 08E, :2 to be operated during the .fourth spacing interval tinstead of the second. iPlane sel'e'ctin gilreyir l .is operated when it is desired :toic'ontrol :all three planes simultaneously. The operations are again similar to those previously described, in this case code selectingrelay 2563 is operated to cause OSC. 2 toibe operated during bothfthenrst and second spacing intervals. The manner in which these codes are employed to effectthe desired plane selection is fully described in the afore-mentioned copen'ding application.

When the quadrant switched is moved forward or backward either O'SC. '9 'or it is operatedpver leads 58 or 4'! to cause the elevators "in the selected plane to be operated accordingly. In a similar manner, 1atera1 movement or "the quadrant switch operates 050.5 or OSC. '6 overloads 5B or M to cause either the rudder aloneyor'both the rudder and ailerons, in thes'el'ected'plane to be operated accordingly. Normally the rudder and ailerons are operated jointly to cause the plane to bank when a turn isexe'c'uted. Inlanding operations, switch 2! is operated 'to'prevent banking when the quadrant switch is moved'laterally. The transmission of a code signal to effect this result is similar to the transmission of a plane selection signal 'except'for the manner of registering the code in'respon'se t'o the operation or release of switch 2!. 'When switch '2! is operated it looks mechanicallyaand closes-a -'cirleads to and so from the quadrant switch to pre- 080. 2 was :reoperatvent any operation of the rudder in the controlled plane while the signal is being transmitted. Relay I operates and closes a circuit to relay i58 from battery on lead 31 if or when the code selecting relays are free. The succeeding operations of relays 156, M39, code selecting relay 2%, etc. are the same as previously described. In addition to the operations described previously the operation of relay i opens the operating circuit to relay M9 and closes the locking circuit to relay H8 at contacts IS!. The operation of relay 2IDS and subsequent release of relays MB and I5!) closes a circuit to relay i3il and to the lower winding of relay it!) from battery over lead 32, through contacts of relay 50 to lead 61, through contacts of relay 2% to lead 68, and through contacts of relays I66 and me. The above circuit to the lower winding of relay IDS is to prevent relay lfifl from being released by the opening of switch 2| during the signal transmission. Relay i313 operates and mechanically releases relay l2fi. Relay I28 restores, mechanically locks relay I38 operated, and opens the operating circuit to relay H9. When the code sig-- nal has been sent as described for the plane selecting operation relays 2G0 and 2188 are released by the operation of relay 3353 thus removing battery from lead 66. Relay Hi8 remains oper ated as long as the circuit to its upper winding is maintained by switch 2i. Relay I38 is deen ergized but is mechanically locked in the operated position by relay I28. The release of relay ems also removes battery from lead 3 3 which releases relay B6B. Relay I69 restores and unlocks relay He at contacts l5]. Relay H5 restores and connects leads 49 and 59 to the quadrant switch. Since none of the leads 4! to M are connected to lead by code selecting relay 2% the code transmitted consists of one operation of OSC. 2 followed by five operations of OSC. I.

When it is desired to return to combined control of rudder and ailerons by the quadrant switch so as to execute banked turns, switch 2! is mechanically released to open the circuit to the upper winding of relay I96. Relay ill-3 restores, closes a circuit to relay Ht, closes a circuit to relay hit! from battery at contacts it, through contacts iii: and contacts of relay I35, prepares a circuit to operate relay 251 from lead 68, and

prepares a circuit to operate code selecting relay 2H3 from lead 68. Relays H0, Mil, etc. operate as before. This time when battery is connected to lead 53 a circuit is closed to relay i253 through back contacts of relay till! and operated contacts of relay i323. Relay E28 operates, opens the operating circuit to relay I it, and mechanically releases relay 139. Relay H50 restores, mechanically locks relay 52$ operated, and opens the operating circuit to relay I29. Relay H6 is released when relay its restores at the end of the transmission and it reconnects leads 59 and to the quadrant switch. As code selecting relay 2m connects lead t! to lead 45 the transmitted code signal will consist of one operation of CS0. 2 followed by live operations of OSC. l

with OSC. 2 reoperated during the first spacing interval.

The operation of the variable function selecting operations of keys C! to CM! is very similar to the plane selecting operations by keys Al to At. A separate start signal register is used comprising relays ill} to 599, each of which controls circuits corresponding to those controlled by the start signal register relays I40 to I68, respectively, associated with the plane selecting keys. Relay H0 is operated by the momentary operation of the common springs CH whenever one of the keys Ci to CH1 is operated to the latching position. Relay i8!) is then operated over lead 3! when the code selecting relays are free. However if relay M0 is operated, indicating that a key in the plane selecting group has been operated and the corresponding code signal has not yet been transmitted, contacts I4! of relay Mil prepare a circuit to relay I50 and prevent the operation of relay Ill] until this plane selecting code has been registered and transmitted. The plane selecting keys are thus given preference because in using the control equipment the function selecting key may often-times be operated immediately after the operation of the plane selecting key corresponding to the plane in which the function is to be performed. When relay I89 does operate it closes a circuit to relay 19% which operates and connects all of the keys Ci to CH3 to the corresponding code selecting relays, 265 to 235), through contacts of relay 290T, which is also operated by relay iSfi over lead 33. The registration and transmission of the code signals is the same as described for plane selection except that a greater number of codes are used and also that OSC. 4 takes the place of OSC. .2. This selection is accomplished by the operation of relay 98 in place of relay 558, thus connecting lead 35 to lead 69 in place of lead 36. Therefore, the first pulse of ground over lead 85 causes the operation of OSC. 4 which causes the seizure of a corresponding register in the controlled planes. At the conclusion of a code signal the relays in the seized register will Spacing Interval Selected Function I l l X X X x x The above code is the same as that used for plane selection and aileron control except that 0S0. 2 was used then instead of OSC. i. The registers in the controlled planes which are associated with OSC. A are arranged to select any one of ten pairs of circuits. Either circuit of a selected pair may be completed by throwing key it to the right or left to operate 050. 7 or 8 over leads 76 or 71. As either one of the selected circuits may be completed for as long an interval as desired they are suitable for the control of continuously variable functions, such as the engine throttle.

The transmission of code signals in response to the operation of one or more of the toggle switches B! to B5 is considerably different than that heretoiore described as regards the registration upon the code selecting relays. For one thing, it is intended that a number of these switches may be operated simultaneously or in rapid succession and that the corresponding codes shall then be transmitted in succession. It is also ntended that these switches may be operated while the transmission of a code due to the operation or a key in one oi the other groups is in progress. Assuming, that switch Bi is thrown to. the right, a circuit is closed from battery over lead 3!, through chain contacts on'relays its and lit, over lead T8,.through switch Bl, contacts of relay 29GB, and contacts. of relay 259T to code selecting relay 2H1. If the code selecting relays are in use this circuit will be open at contacts 2! is and 22 IS. If one of the keys in the other groups has been operated and has not yet been registered the circuit will also be open at contacts of relay [4B or Fill. In the latter case the circuit will not be completed until the code selecting relays become free, the code corresponding to the operated key in the other key groups has been registered and transmitted, and the code selecting relays again become free. When the circuit is completed, relay 2 i 0 operates, prep-ares its locking circuit through relay ZIBS, closes a circuit to relay zsos, and closes a circuit to relay ZidB in multiple with itself. Relay 230s operates. Relay r;

iilcB operates and mechanically releases relay 2MB. Relay 289B restores and opens the operating circuit to relay 2H3 which also removes a short circuit from relay ZlilS. Relay ales operates, closes a circuit to relay 220$ and removes battery from lead 3! to guard the code selectin relays and also opening the circuit to relay 21813. The code signal is tran mitted as previously described. except that OSC. 31 takes the place of 080. 2. This occurs because lead 45 is connected through back contacts of relay 259T to lead 19 and relay 200T is n t operated t this time. The transmitted code thus consists of one operation of OSC. 3 followed by live operations of CS0. i and a secon operation of 080. 3 during the first spacing interval, When switch Bl is returned to the left it closes a circuit to code selecting relay 200 from lead 18, through switch 13!, and contacts of relay 2003 after any previously stored signals have been transmitted. Relay Zilli operates, prepares its locking circuit through relay ZIBS, closes a circuit to relay 230s, and closes a circuit to relay 20013 in multiple with itself, Relay 230s operates. Relay 269B operates, mechanically releases relay EIBB, and opens the operating circuit to relay 200 which also removes a short circuit from relay ZIUS. Relay 210B restores and mechanically locks relay 225B operated. Relay ZIEIS operates and removes battery from lead 18 by cpernng lead 3! at contacts 2!! S. The succeeding operations will not be described as they should be apparent from the preceding description.

If all of the switches, Bl to B5, were operated to the right simultaneously, a circuit would be completed to relays 2m, 23B, 250, 218, and 2953 in multiple. All of these relays would attempt to operate but the operation of any one of them opens the circuit to all of the preceding code selecting relays by means of the chain circuit connected to lead 38. Consequently, only the highest numbered code selecting relay Will remain operated, in this case relay 29! The operation of relay 2% causes the operation of relay 29b3, which mechanically releases relay 2893 and this in turn removes the short circuit from relay 2698 which removes battery from lead 3! to guard the code selecting relays and starts the code transmission. After this first code has been sent relay 2158 is released and battery is again connected to. lead 3!. If none of the push keys CI to Clo or Al t A4 have been operated in the meantime this battery is extended to lead 78 causing code selecting relays ZIO, 230, 250, and 21o to again attempt to operate. This time relay 27!; is the only relay which can remain operated. This cycle of operations is continued until the live codes corresponding to the operation of switches B! to B5 to the right have been transmitted in succession. If any of the push keys is operated during the transmission of these five cdoes relay Mil or H0 will be operated and will extend lead 3! to relay I50 or I80 instead of to lead 1'8 thus causing the code corresponding to the operated push key to be registered and transmitted as soon as the code transmission in progress is completed. The transmission of the remaining codes corresponding to the operations of switches B! to B5 will then be resumed where it was left oil. Of course, some of the switches Bi to B5 may be operated to the left at the same time that others are operated to the right, the description being limited to operations in one direction merely for simplicity.

Having described and illustrated the invention, what is considered new and is desired to secure by Letters Patent is pointed out in the subj oined claims.

What is claimed is:

1. In a code signaling system, a normally inactive code sender adapted to produce a plurality of codes, a plurality of corresponding code se lecting keys therefor having a common mechanical latching means arranged to release a previously operated key when any other key is operated to the latching position, Switching means momentarily operated by said latching means in. response to the operation of one of said keys, means controlled by said switching means for initiating the operation of said code sender to produce code corresponding to such operated key.

2. In a code signaling system, a code sender, a p li y of groups of code selecting keys, each of said groups of keys having common mechanical latch ng means arranged to release a previously operated key when any other key in the group is operated to the latching position, switching means for each group momentarily operated by latching means in response to th operation or" one of the keys in the group, and means for each group controlled by Said. switching means for associating the code sender with the group in which a key is operated in response to such operation.

3. In combination, a plurality of circuits, a plurality of groups of keys, each of said groups of keys having common mechanical latching means arranged to release a previously operated key when any other key in the group is operated to the latching position, switchin means for each group momentarily operated by said latching in response to the operation of one of the keys in the group, and means controlled by said switching means for connecting said plurality of circuits to the group in which a key is operated in response to such operation whereby one of said circuits is completed by the operated key.

m a code signaling system, a code sender, two groups of code selecting keys therefor, said code sender being adapted to transmit different codes successively in response to the simultaneous or overlappin operation of a plurality of control keys in one of said groups, and means re- 11 sponsive to the operation of a key in the other of said groupsduring said transmission for interrupting the transmission at the completion of the code in progress and for causing the code sender to transmit the code corresponding to the operated key in said other group, said means responding to the completion of said last code to cause the code sender to continue the interrupted transmission.

5. In a code signaling system, a code sender and a register, a two-position switch, a pair of mechanically interlocked relays, a second pair of relays in said register, two circuit paths each ex-= tending from a contact of the switch through contacts of said mechanically interlocked relays to one of said second pair of relays, and operating circuits for each of said mechanically interlocked relays including contacts of the second pair of relays, said circuits being arranged so that alternate operation of the switch between said two positions causes a momentary operating circuit to be closed to alternate ones of said second pair of relays in response to each switch operation, to thereby operate said last relays, said code sender controlled by the operation of said second relays for sending the code associated with each one of said second relays.

6. In a code signaling system, a code sender and a register, a pair of mechanically interlocked relays in said register, a second pair of relays, two circuit paths each extending through contacts of said mechanically interlocked relays to one of said second pair of relays, operating circuits for each of said mechanically interlocked relays including contacts of the second pair of relays, and means for closing either of said two circuit paths, said relay contacts being arranged so that alternate closure of said two circuit paths causes a momentary operating circuit to be completed to alternate ones of said second pair of relays in response to each such closure, to thereby operate said last relays, said code sender controlled by the operation of said second relays for sending the code associated with each one of said second relays.

7. In a code signaling system, a code sender, a plurality of register relays, a plurality of pairs of mechanically interlocked relays, each of said mechanically interlocked relays bein associated with one of said register relays, operating circuits for each of said mechanically interlocked relays including contacts of its associated register relay, selecting circuits for each of said register relays including normally closed chain contacts on all of the succeeding register relays and contacts on the mechanically interlocked relays, said selecting circuits being arranged in pairs, and

means for closing either of the selecting circuits of each pair, said relays being arranged so that the corresponding register relays are successively operated in a predetermined sequence in response to the simultaneous closure of a plurality of said selecting circuits, thereby marking said code sender for sending the code associated with each register relay operated.

8. A code sender for a selective signaling system comprising a chain of counting relays and impulsing means therefor, a plurality of code selecting keys, a pairof signal lines, and means responsive to the operation of one of said code selecting keys for causing said counting relays to be sequentially operated by said impulsing means and for connecting one of said signal lines to contacts of one or more of said counting relays, said impulsing means and said counting relays being arranged to transmit a series of impulses over the other signal line in synchronism with the impulsing means and to transmit one or more impulses having a predetermined chronological relation to the impulses of said series which is characteristic of the operated key over said one signal line.

9. A code sender for a selective signaling system comprising a chain of counting relays and impulsing means therefor, a plurality of groups of code selecting keys, a plurality of signal lines each corresponding to one of said groups, a common signal line, and means responsive to the operation of a code selecting key in one of said groups for causing said counting relays to be sequentially operated by said impulsing means and for associating the signal line corresponding to said one group with the counting relays, said impulsing means and said counting relays being arranged to transmit a series of impulses over the common signal line and to transmit one or more impulses having a predetermined chronological relation to the impulses of said series over the signal line associated with the counting relays.

HARRY G. EVERS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

